Optimising prenatal diagnosis of Down's syndrome

Following an editorial in the BMJ on optimising prenatal diagnosis of Down’s syndrome (1), a recent report by Dhallan et al (2) on the potential for risk-free prenatal diagnosis of Down’s syndrome (DS) by the use of maternal blood samples alone has attracted much media attention. There have also recently been a number of other reports (3,4) indicating that this might soon become a viable alternative to current prenatal diagnosis, where unfortunately amniocentesis and chorionic villus sampling (CVS) are associated with a fetal loss rate of around 0.5-1%.